Performance of cable risers in a dynamic environment

Abstract

This paper examines, using real data and modelling techniques, the potential faults that can occur in a cable placed in a dynamic environment. It explains why protection sheaths are undesirable in cable risers for most offshore dynamic applications. the paper goes on to explain the desired design characteristics of the cable riser and how these can be met by appropriate design of the structure of its concentric layers. The paper also suggests that high stresses and dynamic tensions are almost inevitable going to exist in a cable especially in the vicinity of the touchdown point that is exposed for prolonged periods in a dynamic environment and explains how these are affected by water depth. The paper concludes that dynamic cables from the sea surface to the seabed are a specialist design and are application dependent. The results are obtained from the research are discussed with particular focus on one shallow and one deep water application.